Crown crowning is a surgical procedure performed by a dentist, or more often a periodontist specialist. There are a number of reasons to consider crown lengthening in the treatment plan. Generally, this procedure is used to expose large amounts of dental structures for the purpose of further restoring the teeth prosthetically. However, other indications include accessing subgingival caries, accessing perforations and to treating aesthetic imbalances such as smiles. There are a number of procedures used to achieve an increase in crown length.
Video Crown lengthening
Pertimbangan biomekanik
Lebar biologik
Biological width is the distance defined by "junctional epithelium and attachment of connective tissue to the root surface" of the tooth. In other words, it is the height between the deepest point of the gingival sulcus and the peak of the alveolar bone. This distance is important to consider when fabricating dental restorations, as they must respect the natural architecture of gingival attachments if dangerous consequences should be avoided. The biological width of the patient is specific and may vary anywhere from 0.75 to 4.3 mm.
Based on a 1961 paper by Gargiulo, the average biologic width is determined to be 2.04 mm, of which 1.07 mm is occupied by connective tissue connections and another 0.97 mm approximation is occupied by junctional epithelium. Since it is not possible to completely restore the tooth to the right coronal edge of the junctional epithelium, it is often recommended to remove enough bone to have 3mm between the restoration margin and the peak of the alveolar bone. When restorations do not take this into account and break the biological width, three things tend to happen:
- chronic pain
- chronic inflammation of the gingiva
- unpredictable alveolar bone loss
Ferrule effect
In addition to the crown lengthening to form a proper biological width, a 2 mm tooth structure should be available to allow for the ferrule effect. Ferrule, with respect to the teeth, is a band that encircles the external dimensions of residual tooth structure, unlike metal bands that surround the barrel. Adequate vertical altitude of the tooth structure to be grasped by a future crown is required to allow future prosthetic crown ferrule effects; has been shown to significantly reduce the incidence of fractures in endodontically treated teeth. Since the structure of the inclined tooth is not parallel to the vertical axis of the tooth, it does not properly contribute to the high ferrule; thus, the desire to tilt the crown limit of 1 mm would require an additional 1 mm of bone removal in the crown lengthening procedure. Often, however, restoration is done without such bevel.
Several recent studies have shown that, while ferrule is certainly desirable, it should not be given at the expense of remaining tooth/root structures. On the other hand, it has also been shown that "the difference between effective long-term restoration and failure can be as small as 1 mm from additional dental structures which, when wrapped by ferrule, provide great protection." When long-term functional recovery is unpredictable, dental extraction should considered. "
Between-to-root ratio
The alveolar bone that surrounds a tooth naturally surrounds the adjacent teeth, and removing the bone for crown elongation procedures will effectively damage bone support to adjacent teeth to some extent inevitable, and increase the crown-to-root ratio. Additionally, once the bone is removed, it is almost impossible to return it to the previous level, and if the patient wishes to install the implant in the future, there may not be enough bone in the area after the crown elongation procedure has been performed. complete. Thus, it would be wise for the patient to thoroughly discuss all of their treatment plan options with their dentist before undergoing irreversible procedures such as crown lengthening.
Care planning
Crown elongation is often performed in conjunction with some other costly and time consuming procedures where the combined goal is to correct the prosthetic forecast of the tooth. If the tooth, due to the relative lack of solid tooth structure, also requires post and core, and thus, endodontic treatment, total combined time, effort and cost of various procedures, and disproportionate prognosis due to the combination of failure rates attached to each procedure, may join to make it sensible to pull teeth. If patients and extraction sites make for eligible candidates, it is possible to place implants placed and recovered with more aesthetic, timely, inexpensive and reliable results. It is important to consider the many options available during the stage of dental care planning.
An alternative to surgical crown elongation is orthodontically imposed eruption, it is non-invasive, does not eliminate or damage bone and can be cost-effective. Teeth extruded several millimeters with a simple bracketing of adjacent teeth and using this lightweight power will only take a few months. Seratotomy is performed after elongation of the crown and is easily performed by a general dentist. In many cases as this is indicated, surgery and extraction can be avoided if the patient is treated orthodontically rather than periodontally.
Maps Crown lengthening
Crown Elevation Technique
Flap Repositioned Apposed with Osseous Recontouring (Resection)
Apical reposition flap is a widely used procedure that involves flap elevation with subsequent osseous contours. The flap is designed in such a way that it is replaced more apical to its original position and thus the direct exposure of the sound gear structure is obtained. As discussed above, when planning consideration of crown elongation procedures should be given for maintenance of biological width.
As a general rule, at least 4 mm of sound tooth structure should be exposed at the time of operation. This therefore permits supracrestal soft tissue proliferation, which is estimated to cover 2 to 3 mm of the coronal root structure thus leaving 1 - 2 mm of supragingival tooth structure. Furthermore, the mind must be given to the tendency attached to the gingival tissue to bridge sudden changes in the bone-top contour. It is thus recommended that bone dewatering should be performed not only around troubled teeth but also on adjacent teeth to gradually reduce the osseous profile.
As a result, a large number of attachments may have to be sacrificed when the crown lengthening is done by apically placed flap technique. It is also important to remember that, for aesthetic reasons, the symmetry of the length of the tooth must be maintained between the right and left side of the dental arch. This may, in some situations, require the inclusion of more teeth in surgical procedures.
Indication:
The crown of a double tooth in a quadrant or a sextant of a tooth
Contraindications:
Single teeth in the esthetic zone are becoming more damaging
Technique:
- The reverse incision is made using a scalpel. This initial incision is guided by pre-operative planning and is based on the number of tooth structures to be exposed. Beveling incisions should also follow the sketch line, to ensure maximum interproximal coverage of the alveolar bone when the next flap is repositioned. The vertical incision releases extends outward into the alveolar mucosa, passing through the mucogingival junction, created at each end point of the back incision, thus making apical repositioning of the flap possible.
- The thick mucoperiosteal mucous membrane is then removed to expose the root surface. The flap, combining buccal/lingual gingivae and alveolar mucosa, must then be elevated above the mucogingival line so that it can later reposition the soft tissues apically. The link of marginal tissue is then removed with a curette.
- The osseous reconstruction is then performed using a spinning round bur and excessive water spray or bone chisel. Reconstruction should aim to recreate the normal form of alveolar peaks, but at a more apical level.
- After osseous surgery, the flap is repositioned to the peak level of the newly re-contracted alveolar bone and secured in position. Full soft tissue coverage is inherently more difficult and therefore, periodontal dressings should be applied to protect the bare interproximal alveolar bone to maintain soft tissue at the peak level of the bone.
Advantages:
An immediate increase in the sound gear structure can be achieved
Disadvantages:
Procedures are difficult for the patient to tolerate, improve post-operative pain
Forced Gear Disorders
Orthodontic tooth movement can be used to erupt teeth in adults. If eruption force is being applied, the entire eruption apparatus will move along with the teeth. Thus, the required unit should be extruded at a distance equal to or slightly longer than the sound part of the tooth structure which will be exposed in the following surgical treatments. Once stabilized, the full thickness flap is then elevated and an osseous recontain is performed to expose the required tooth structure. It should be noted that to restore the aesthetic proportions properly the hard and soft tissues of adjacent teeth should remain unchanged.
Indication:
Forced dental eruptions are indicated where elongation of the crown is required, but the attachment and bone of adjacent teeth should be maintained.
Contraindications:
Forced dental eruptions require fixed orthodontic appliances. This poses a problem in patients with declining teeth, in which case an alternative crown elongation procedure should be considered
Technique:
The orthodontic bracket is attached to a tooth which requires a crown elongation operation and then to adjacent teeth, these are then combined in the archwire. The elastic band power is then tied from the bracket to the archwire (or bar), which pulls the teeth coronally. Direction of the movement of the tooth should be checked carefully to ensure no tilting or adjacent tooth movement occurs.
Forced Dental Eruptions can also be done with fiberotomy. This technique is adopted when the gingival margins and the height of the crystal bone should be maintained at their pretreatment site. Seratotomy is performed at 7-10 days intervals during treatment. Skalpel is used to cut the supracrestal connective tissue fibers, thus preventing the crystal bone following the roots in the coronal direction.
Advantages:
Maintain the osseous structure around the adjacent teeth
Disadvantages:
Procedures require fixed wire placement and maintenance time may be extended
References
Source of the article : Wikipedia
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